Electric furnace for the manufacture of carbon disulphide



PHIDE C. PAOLONI May 10, 1955 ELECTRIC FURNACE FOR THE MANUFACTURE OF CARBON DISUL Filed Oct. 2. 1952 INVENTOR. CARL 0 P401. o/v/ A TTOA /VEY ELECTRIC FURNACE FOR THE MANUFACTURE OF CARBON DISULPHIDE Carlo Paoloni, Turin, Italy, assignor to Rumianca S. p. A., Turin, Italy Application October 2, 1952, Serial No. 312,763 Claims priority, application Italy September 2, 1952 4 Claims. (Cl. 23-477) A number of electric furnaces for manufacturing carbon sulphide by reaction of sulphur on carbonaceous material electrically heated by direct flow of electric current are known.

All these electric furnaces sulfer from the serious r drawback of producing a relatively small quantity only of carbon disulphide by volume unit of carbonaceous mass filled and heated therein. A further drawback resides in the fact that these furnaces cannot advantageously employ carbonaceous materials other than charcoal, while it would be desirable to utilise further carbonaceous materials such as petroleum coke, pitch coke, semi-coke etc. This is chiefly due to the fact that most of the carbon volume submitted to the electric current is either utilised as a mass for evaporating sulphur, or as a filter for retaining sulphur carried along by carbon disulphide.

In fact, electric furnaces for manufacturing carbon disulphide, with the exception of furnaces embodying retorts heated externally by means of electric resistances, may be subdivided into two main groups. The former includes electric furnaces embodying a crucible of large section and an overlying high column of smaller section. The large crucible encloses the electrodes which heat by arc-resistance the coal and cause the sulphur to vaporize.

A serious drawback of these furnaces resides in the fact that the strongest heat is evolved at their lower portion and results in an excessive overheating; consequently, the effectively reactive portion of the coal is minimized, while most of the coal in the vertical overlying column merely serves to retain from the overheated vapours unreacted sulphur accompanying the carbon disulphide.

As a consequence, in order to procure 1 ton carbon sulphide per day, a volume of 10 to 12 cubic meters charcoal should be employed in the furnace.

The second group of electric furnaces includes superposed electrodes column furnaces, in which the electrodes are spaced from the furnace wall in order to localise maximum heating at given regions only.

In this case also, the effectively reactive coal volume is very small, while most of the coal submitted to the electric current serves for vaporising the sulphur, the remaining coal portion serving for retaining or filtering the unreacted vaporised sulphur.

The consequence is that also in these furnaces, in order to produce 1 ton per day carbon sulphide 4 to 5 cubic meters charcoal should be employed.

These superposed electrode furnaces are distinguished namely by the small section of their electrodes and the spaced relationship of the latter to the furnace walls. Therefore, heat is concentrated on the uppermost electrode only and the reactive region is indeed very small. Most of the coal volume is inert and merely contributes to the increase of the furnace size.

This invention concerns a novel electric furnace capable of producing over 1 ton carbon disulphide in 24 nited States Patent 0 ill Patented May 10, 1955 hrs. from 1 cubic meter heated coal, which is an important advantage, since it means that, the coal quantity or volume being the same, the output is 4 to 5 times that of electric furnaces known heretofore. Moreover, carbonaceous materials such as petroleum coke, pitch coke, semi-coke or even less reactive coals, such as anthracite etc., may be employed in the novel furnace, besides charcoal. The technical advantage of this invention will be obvious, for it is known that even externally heated retorts do not succeed in economically producing carbon sulphide from carbonaceous materials other than charcoal. The high specific output of the furnace according to this invention makes it possible to manufacture electric furnace of a specific capacity of l0lS 20 tons per day carbon disulphide, while it is known that at present more than 2-3-4 tons/day with retorts or 3-4-5 tons/day with electric furnaces can never be obtained per unit.

The improved capacity by volume unit results in reduced installation cost, lower specific consumption, reduced cost of work and upkeep.

The electric furnace according to this invention con sists mainly of two concentric vertical cylindrical portions, separated from each other by a refractory cylindrical partition having radial holes therein. The cylindrical inner portion receives the carbonaceous material which is electrically heated by means of superposed electrodes while the annular portion comprised between the partition and the outer wall, receives the sulphur and is filled with noncarbonaceous material which is heated by radiation through the holes in the partition, in order to cause the sulphur to vaporise, the vaporized sulphur flowing through the holes in the partition and reacting with the Whole central coal column. As distinct from all electric furnaces known heretofore, in which a small coal portion only reacts, 100% of the coal in our improved furnace actually reacts, thereby strongly increasing the carbon disulphide production by volume unit.

The possibility of bringing the whole vertical coal column to the reaction temperature and vaporizing sulphur merely by effect of the heat radiation of said column is the chief departure from all furnaces known heretofore. Since at the reaction temperature, the reaction of sulphur vapours on coal is an exothermic one,

that is, it evolves heat, this excess heat is moderated and utilised by radiation from the incandescent central chamber through the holes in the partition, thereby heating the noncarbonaceous filling material which yields heat to the sulphur. The separate vaporizing of the sulphur on the non carbonaceous filling material is advantageous inasmuch as any impurities in the sulphur do not reach, as in present furnaces, the carbonaceous material and choke the pores or objectionably affect the reactivity of the carbonaceous material.

On account of radiation and how of sulphur vapours, the partition, although it is made of highly refractory material, is not subjected to excessive heat and chemical stresses and its life is satisfactory. The holes in the partition may be cylindrical, conical, quadrangular, etc. The noncarbonaceous filling material is material unatlacked by sulphur and resistant to high temperatures such as fused alumina, and is either in irregular lumps or in the form of well defined geometrical bodies having an extensive surface by volume unit.

The accompanying drawing shows by Way of a nonlimiting example and diagrammatically an embodiment of the furnace according to this invention.

Figure l is an axial section of the furnace; Figure 2 shows the furnace associated with a device for separat- "ig sulphur from the carbon disulphide.

The furnace comprises an inner cylindrical portion A filled with carbonaceous material 1, a partition B having radial holes F therein, an annular portion C filled with noncarbonaceous filling material 2 and an outer casing D. The cylindrical portion A filled with the carbonaceous material is heated by superposed electrodes E1 and E2 equalling in diameter the carbonaceous column. The upper electrode Er has a ring shaped form and the lower electrode E2 is in the form of a disc. Sulphur is admitted at 3 in a uniform distribution in a liquid state on the annular chamber C and evaporated on the noncarbonaceous material 2, whereupon it flows in vapour form through the holes F and reacts with the mass 1.

The furnace is provided with a top outlet 2b for the produced carbon disulphide and with an inlet W for supplying the carbonaceous material from a hopper 4.

In order to further reduce the carbon volume, more particularly also at the upper portion and maintain a very high output it has been found convenient, according to this invention, to connect the furnace with a sulphur separator and condenser, so that separated sulphur can be promptly re-cycled. This dispenses from providing over the reactive coal portion a high coal column as in electric furnaces known heretofore, in which coal serves as a filter for retaining any sulphur carried along by carbon disulphide. This provision according to the invention gives practically sulphur-free carbon disulphide, notwithstanding the high carbon sulphide output.

Figure 2 shows the furnace associated with this separator 5 comprising a container R carrying a liquid sulphur bath which can be kept at the desired temperature by means of submerged coils P. The carbon disulphide vapors containing sulphur are caused to bubble through the bells M in the liquid sulphur and sulphur is condensed, while carbon disulphide is fed further in vapor form.

The sulphur separated through a siphon conduit N is returned to the furnace. While in all electric furnaces any high output is limited by soiling of carbon disulphide with sulphur, the above arrangement permits of further improving the already very high output.

It has been ascertained that since the whole carbonaceous mass is sufficiently heated in the improved furnace, carbonaceous materials other than charcoal, such as petroleum coke, pitch coke, semi-coke, anthracite, etc. can be employed for manufacturing carbon disulphide with high output. Petroleum coke deserves particular attention, since it yields in the novel furnace an output at least as high as charcoal, which is a considerable improvement over all furnaces known heretofore in which, as is well known, petroleum coke yields an output which is 1 to A as compared with charcoal.

What I claim is:

1. An electric furnace for the manufacture of carbon disulphide from sulphur and carbonaceous material which comprises an outer casing and a vertical refractory partition in said casing defining two concentric vertical chambers, the inner chamber thereby defined being adapted to be supplied with carbonaceous material, means for electrically heating the contents of the inner chamber comprising vertically-spaced superposed electrodes positioned at the top and bottom of said refractory partition and said partition being provided with radial holes disposed between said electrodes, and non-carbonaceous subdivided filling material disposed in the outer chamber, said outer chamber being adapted to have sulphur introduced therein, said sulphur becoming heated and vaporized by radiation of heat from the carbonaceous material in the inner chamber and passing through the holes in said partition when the furnace is in operation.

.2. An electric furnace for the manufacture of carbon disulphide from sulphur and carbonaceous material which comprises an outer casing and a vertical refractory partition in said casing defining two concentric vertical cham bers, the inner chamber thereby defined being adapted to be supplied with carbonaceous material, means for electrically heating the contents of the inner chamber comprising vertically spaced superposed electrodes positioned at the top and bottom of said refractory partition and said partition being provided with radial holes disposed between said electrodes, non-carbonaceous subdivided filling material disposed in the outer chamber, means for introducing sulphur into said outer chamber, said sulphur becoming heated and vaporized by radiation of heat from the carbonaceous material in the inner chamber and passing through the holes in said partition when the furnace is in operation, and means for removing reaction products from said inner chamher.

3. An apparatus for the manufacture of carbon disulphide from sulphur and carbonaceous material which comprises an outer casing and a vertical refractory partition in said casing defining two concentric vertical chambers, the inner chamber thereby defined being adapted to be supplied with carbonaceous material, means for electrically heating the contents of the inner chamber comprising vertically spaced superposed electrodes positioned at the top and bottom of said refractory partition and said partition being provided with radial holes disposed between said electrodes, non-carbonaceous subdivided filling material disposed in the outer chamber, means for introducing sulphur into said outer chamber, said sulphur becoming heated and vaporized by radiation of heat from the carbonaceous material in the inner chamber and passing through the holes in said partition when the furnace is in operation, and means for removing reaction products from said inner chamber, said last-named means including a sulphur separator adapted to contain a molten sulphur bath, means for maintaining said bath in a molten condition, and con duit means for returning to said outer chamber the sulphur separated in the separator.

4. An electric furnace for the manufacture of carbon disulphide from sulphur and carbonaceous material which comprises an outer casing and a vertical refractory partition in said casing defining two concentric vertical chambers, the inner chamber thereby defined being adapted to be supplied with carbonaceous material, means for electrically heating the contents of the inner chamber comprising vertically spaced superposed electrodes positioned at the top and bottom of said refractory partition and said partition being provided with radial holes disposed between said electrodes, and non-carbonaceous subdivided filling material disposed in the outer chamber, said filling material comprising geometrical bodies having an extensive surface, said outer chamber being adapted to have sulphur introduced therein, said sulphur becoming heated and vaporized by radiation of heat from the carbonaceous material in the inner chamber and passing through the holes in said partition when the furnace is in operation.

References Cited in the file of this patent UNITED STATES PATENTS Re. 22,274 Gardner Feb. 23, 1943 688,364 Taylor Dec. 10, 1901 702,117 Taylor June 10, 1902 706,128 Taylor Aug. 5, 1902 805,502 Taylor Nov. 28, 1905 957,058 Hixon May 3, 1910 985,226 Taylor Feb. 28, 1911 1,174,667 Bucher Mar. 7, 1916 1,174,668 Bucher Mar. 7, 1916 2,386,189 Bagley Oct. 9, 1945 FOREIGN PATENTS 542,746 France May 22, 1922 

3. AN APPARATUS FOR THE MANUFACTURE OF CARBON DISULPHIDE FROM SULPHUR AND CARBONACEOUS MATERIAL WHICH COMPRISES AN OUTER CASING AND VERTICAL REFRACTORY PARTITION IN SAID CASING DEFINING TWO CONCENTRIC VERTICAL CHAMBERS, THE INNER CHAMBER THEREBY DEFINED BEING ADAPTED TO BE SUPPLIED WITH CARBONACEOUS MATERIAL, MEANS FOR ELECTRICALLY HEATING THE CONTENTS OF THE INNER CHAMBER COMPRISING VERTICALLY SPACED SUPERPOSED ELECTRODES POSITIONED AT THE TOP AND BOTTOM OF SAID REFRACTORY PARTITION AND SAID PARTITION BEING PROVIDED WITH RADIAL HOLES DISPOSED BETWEEN SAID ELECRODES, NON-CARBONACEOUS SUBDIVIDED FILLING MATERIAL DISPOSED IN THE OUTER CHAMBER, MEANS FOR INTRODUCING SULPHUR INTO SAID OUTER CHAMBER, SAID SULPHUR BECOMING HEAT AND VAPORIZED BY RADIATION OF HEAT FROM THE CARBONACEOUS MATERIAL IN THE INNER CHAMBER AND PASSING THROUGH THE HOLES IN SAID PARTITION WHEN THE FURNACE IS IN OPERATION, AND MEANS FOR REMOVING REACTION PRODUCTS FROM SAID INNER CHAMBER, SAID LAST-NAMED MEANS INCLUDING A SULPHYR SEPARATOR ADAPTED TO CONTAIN A MOLTEN SULPHUR BATH, MEANS FOR MAINTAINING SAID BATH IN A MOLTEN CONDITION, AND CONDIUIT MEANS FOR RETURNING TO SAID OUTER CHAMBER THE SULPHUR SEPARATED IN THE SEPARATOR. 